django-reverse-proxy-send-file 1.0.2

Storage and View to send X-Accel-Redirect (or X-Sendfile) header to nginx (or apache) reverse-proxy

django-reverse-proxy-send-file

Sumary

This package help writing views which use the X-Accel-Redirect header to have nginx serving files but still allow a permission check at django's side

Intro

The storage.ReverseProxySendFileFileSystemStorage class is a drop-in replacement of django's FileSystemStorage which make FileField (or ImageField) url to use the REVERSE_PROXY_SENDFILE_MEDIA_URL settings base url instead of MEDIA_URL

The storage.ReverseProxySendFileStorageMixin allow you to apply the overriden base_url on any storage class

The ReverseProxySendFileView class handle GET request and return an empty response with nginx's X-Accel-Redirect header to order nginx to return the file at given path. The REVERSE_PROXY_SENDFILE_MEDIA_ROOT setting must be defined in the nginx context si it can find the file

The ReverseProxySendFileView can be overrided to implement a custom check_permission method which verify is the current user is allowed to download the resource.

Installation

Install the django-reverse-proxy-send-file pypi package. ex:

• poetry add django-reverse-proxy-send-file
• pip install django-reverse-proxy-send-file

Usage

See example section bellow

Settings

Name	Default	Description
REVERSE_PROXY_SENDFILE_MEDIA_ROOT	MEDIA_ROOT	Base path in django's context where to store media files when uploaded (used by Storage class)
REVERSE_PROXY_SENDFILE_MEDIA_URL	"smedia/"	URL that handle the resources that should be served by the reverse proxy.
REVERSE_PROXY_SENDFILE_REVERSE_PROXY_ROOT	"smedia/"	Base path in reverse-proxy's context which is sent back to reverse-proxy in header so it can find the file
REVERSE_PROXY_SENDFILE_MODE	"nginx"	Possible values: "nginx" or "apache". nginx mode will use X-Accel-Redirect header. apache mode will use X-Sendfile
REVERSE_PROXY_SENDFILE_HEADER_NAME	None	A custom header name. If set this header will be used regardless REVERSE_PROXY_SENDFILE_MODE setting.
REVERSE_PROXY_SENDFILE_DEBUG_SERVE_RESOURCE	True	In django's DEBUG mode, the resource is directly served by the dev server.

Exemple

settings.py

...
REVERSE_PROXY_SENDFILE_MEDIA_URL = "smedia/"
REVERSE_PROXY_SENDFILE_MEDIA_ROOT = "/django_path/to/smedia/"
REVERSE_PROXY_SENDFILE_REVERSE_PROXY_ROOT = "/nginx_path/to/smedia/"
...

models.py

from django.contrib.auth.models import User

from reverse_proxy_send_file.storage import ReverseProxySendFileFileSystemStorage

class MyModel(models.Model):
    ...
    user = models.ForeignKey(User, on_delete=models.CASCADE)
    my_file = models.FileField(
        "My file",
        upload_to="my_files/",
        storage=ReverseProxySendFileFileSystemStorage(),
    )
    ...

views.py

from django.http import Http404

from reverse_proxy_send_file.views import ReverseProxySendFileView

class ReverseProxySendFileMyFileView(ReverseProxySendFileView):
    def check_permission(self, request, resource_url, *args, **kwargs):
        obj_qs = MyModel.objects.filter(my_file=resource_url)
        if not obj_qs.exists():
            raise Http404()
        return obj_qs.filter(user=request.user).exists()

urls.py

from django.conf import settings
from views import ReverseProxySendFileMyFileView

urlpatterns = [
    ...
    re_path(
        settings.REVERSE_PROXY_SENDFILE_MEDIA_URL + "(?P<resource_url>my_files/.*)$",
        views.ReverseProxySendFileMyFileView.as_view(),
        name="reverse_proxy_send_file",
    ),
    ...
]

1. User upload file. The file is stored in /django_path/to/smedia/my_files/blop.pdf
2. User access /smedia/my_files/blop.pdf
3. A django request is performed and it check file access permission for current user (in check_permission).
4. • If the user is allowed return a HTTP response with header : X-Accel-Redirect=/nginx_path/to/smedia/my_files/blop.pdf (Nginx will use it to send the file to the client)
   • If the file os not found return a 404 note found.
   • If the user id forbidden, return a 403 response forbidden

Setup dev environnement

# install dev dependencies
poetry install --no-root
# install git pre-commit
pre-commit install

Run tests

Use tox command to run all tests on all supported python versions Examples:

tox
tox -e py38-django40
tox -f py39

Build package and publish on PyPI

Change version number in pyproject.toml

poetry build
poetry publish